The brutal murder of a lottery winner has Castle and Beckett up to their eyeballs in suspects, envious and angered by the victim's sudden move from the poorhouse to the penthouse. As the precinct buzzes with fantasies of what our cops would do if they won the lottery, Martha struggles with the reality of such a decision when she suddenly inherits money she feels she doesn't deserve.

Castle and Beckett investigate the apparent robbery-homicide of a New York cab driver, only to discover that the victim was involved in a mysterious conspiracy with unimaginable consequences. As the stakes continue to rise, hard-charging federal agent Mark Fallon takes over the investigation. Together, Fallon, Beckett and Castle must race to unmask the truth about the victim before it's too late.